Reusing Program Investigation Knowledge for Code Understanding

Software maintenance tasks typically involve an important amount of program investigation effort on the part of software developers. To what extent can we benefit from prior program investigation activities to decrease this effort? To investigate this question, we studied the revision history of two systems to determine how knowledge derived from prior investigation activities could have been reused to support other change tasks. Our initial investigation used a tool, ConcernDetector, that can recommend sets of program elements associated with a high-level concern when elements in the set overlap with elements currently being modified. We discovered that simple overlap-based techniques for retrieving prior investigation knowledge have important limitations, and that effective reuse of prior program investigation knowledge requires analyses that can partially infer the nature and intent of a task.